#: 231 - 240

#

NameYearCountryScience

achievements

231

Charles Glover Barkla

1877-1944United KingdomPhysics

discovered that every chemical element, when irradiated by x rays, can emit an x-ray spectrum of two line-groups, which he named the K-series and L-series, that are of fundamental importance to understanding atomic structure

232

Johannes Stark

1874-1957GermanyPhysics

discovered splitting of spectral lines in a strong electric field

233

Georges Sagnac

1869-1928FrancePhysics

Sagnac effect; X-ray fluorescence

234

Pieter Zeeman

1865-1943NetherlandsPhysics

discovered splitting of spectral lines in a strong magnetic field

235

Wilhelm Wien

1864-1928GermanyPhysics

discovered laws governing radiation of heat

236

Marcel Brillouin

1854-1948FrancePhysics

built a new model of the Eotvos balance; Helmholtz flow and the stability of aircraft; theory of the tides

237

Janne Rydberg

1854-1919SwedenPhysics

analyzed the spectra of many elements; discovered many line series were described by a formula that depended on a universal constant (the Rydberg constant)

238

John Henry Poynting

1852-1914United KingdomPhysics

demonstrated that the energy flow of electromagnetic waves could be calculated by an equation (now called Poynting's vector)

239

George Francis FitzGerald

1851-1901IrelandPhysics

hypothesized foreshortening of moving bodies (Lorentz-FitzGerald contraction) to explain the result of the Michelson-Morley experiment

240

Oliver Heaviside

1850-1925United KingdomPhysics

contributed to the development of electromagnetism; introduced operational calculus and invented the modern notation for vector calculus; predicted existence of the Heaviside layer (a layer of the Earth's ionosphere)